A hydrogen fuel cell system typically includes a fuel cell stack including multiple, stacked fuel cells. Each fuel cell has a polymer electrolyte membrane (PEM) sandwiched between a cathode and an anode. The fuel cell stack is contained within a fuel cell enclosure. During operation of a hydrogen fuel cell system, some nitrogen from air in the oxidant gas of the cathode crosses over from the cathode side to the anode side of each fuel cell stack due to a gradient in nitrogen concentration. This nitrogen crossover leads to lower hydrogen fuel concentration in the anode side of the fuel cell stack, compromising fuel cell performance.
In order to remove nitrogen from a fuel cell stack, the stack is periodically purged. However, when purging nitrogen from the fuel cell stack, some hydrogen is released from the stack with the nitrogen. Furthermore, when the anode of the fuel cell stack is pressurized, some hydrogen escapes from the fuel cell stack through seals between the cells. This hydrogen is typically vented from the fuel cell stack enclosure. Therefore, fuel hydrogen is lost through several different aspects of fuel cell operation.
Accordingly, a system and method are needed which are capable of reclaiming hydrogen lost from a fuel cell system during fuel cell operation.